Carburetor



Dec. s, 1942. Y R. w. ENGNATl -l 2,304,247 h Q NNNNNN O R RICHARD w. GNATH' M wmm m R. w. ENGNATH Dec. 8, 1942. I

CARBURETOR Fild Oct. so, 1940 4 sheets sheet 2 v I 1 mvs'mba RICHARD W. ENGNATH Dec. 8, 1942. i R. w. ENGNATH 2,304,247

lNVENTOR RICHARD W. E NGNATH ATTORNEYS 1942. R. w. ENGNAfH 2,304,247

CARBURETOR.

Filed Oct 30, 1940 4 Sheets-Sheet 4 INVENTOR I RICHARD W. ENGNATH Patented Dec. 8, 1942 UNITED STATES OFFICE CARBURETOR Richard W. Engnath, Brooklyn, N. Y. Application October 30, 1940, Serial No. 363,400

4 Claims.

be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Figure 1 is a side elevation of a typical and illustrative embodiment of the present invention;

Figure 2 is a horizontal sectional view taken on the line 22 of Figure 1;

Figure 3 is a, fragmentary vertical sectional view taken on the line 33 of Figure 2;

Figure 4 is a fragmentary detailed sectional view taken on the line 44 of Figure 3;

Figure 5 is a vertical sectional view taken on the line 55 of Figure 2;

Figure 6 is a vertical sectional the line 6-6 of Figure 1;

Figure 7 is a fragmentary sectional view taken on the line 1-7 of Figure 5 and showing the valve in closed position;

Figure 8 is a similar sectional view showing the valve in its open position;

Figure 9 is a detailed side elevation, with a part broken away and showing the outer portion of the valve f Figures '7 and 8; and

Figure 10 is a similar view of the internal portion of the valve shownin Figures land 8.

The present invention has for its object the provision of a novel and improved carburetor for volatile liquid motor fuels particularly for use with internal combustion engines. The invention also provides an improved carburetor in which substantially complete volatilization of the liquid motor fuel is produced before the fuel is introduced into the intake of the internal combustion engine. Another object of the invention is the provision of a carburetor in which an accurately regulable amount of a rich fuel-air mixture is view taken on fed to a larger quantity of air in the intake to form the explosive intake mixture for the engine. The invention also provides a carburetor having a plurality of premixing chambers which are regulably connected to the intake to supply the correct fuel-air mixture to the engine.

invention has for another object the provision of a carburetor in which a throttled, substantially saturated fuel-air mixture is fed to the intake and mixed with air to be fed to the engine. The invention has for still another object the provision of an improved carburetor which is not liable to become clogged with dirt or foreign material, which eifects substantial fuel economies in the running of the engine, and efliciently produces a fuel-air mixture for combustion in the engine at all operating conditions of the engine.

Referring now in detail to the present and preferredembodiment of the invention as illustrated in the accompanying sheets of drawings, the intake comprises a generally vertically extending.

tube ill of a diameter suflicient for the volumetric capacity of the engine with which it is to be used. Air is admitted to the intake at its lower end H and after being mixed'with vaporized fuel is fed to the engine from the upper end l2 of the intake tube l0.

Intermediate the ends of the tube I0 is provided the throttle valve l5 of substantially conventional construction which is mounted for rotation on a shaft l6 connected with the accelerator pedal or other control member (not shown), and this valve l5 may be rotated in the direction of the arrow (Figure 6) to move it to open position to increase the power of the engine, by increasing the volume of air passing through the manifold.

Below the throttle valve I5 is provided another valve which is normally substantially closed and is opened by the suction of the air drawn by the engine through the manifold Ill against the tension of springs. This valve may comprise the pair of pivoted leaves I! mounted on their shafts [8 in the side walls of the lower portion of the tube I E1. The leaves I! preferably have fairly close contact at their sides with the parallel walls I9 01' the valve chamber 20. Each of the valve leaves H is formed with a downwardly depending lug 2! to which is connected the upper end of a coil spring 23, the lower ends of springs 23 being connected to a yoke 24 which is adjustably supported by means of the locked screw 25 threaded into the lower elbow portion of the tube end H.

With the engine idling, the leaves I! are substantially closed (Figure 6) and the major portion of the air passing through the intake is introduced through air filter 5| and tube5l). As the throttle is opened, the suction is increased on the upper surface of the leaves l1 so that they are swung open against the tension of the springs 23 a sufiicient amount to allow the proper quantity of air to pass into the tube In.

Adjacent the manifold is maintained a small reservoir of fuel and for this purpose there is provided a float chamber which is preferably Th W ented to the atmosphere as by the vent port 86, Fig. 5, into which fuel is delivered from the main fuel supply through the fuel pipe 3| under control of the float 32 which regulates the level of the fuel in the reservoir to maintain it constant in the usual manner by means of a valve (not shown) controlled by the float. The reservoir is formed with a plurality of small depressionss 33, of which three are shown, into which atomized fuel is sprayed with a substantial amount of air to produce a rich and partially saturated fuel-air mixture which is sucked into the intake tube l to be mixed with additional air and be fed to the engine. Premixing chamber 48 is normally disconnectedfrom chamber 4| by means of the valve 43 which normally covers the intercommunicating aperture 46 and is lightly held in closed position by means of the coil spring 44 and stud 45, so that the valve may be opened whenever there is a slightly greater pressure of air within the chamber 40 than in the chamber 4|.

Chambers 40 and 4| are connected with the intake tube is, as will be further described in detail, and .during the running of the engine there is a reduced pressure .in each of them. The rich air-fuel mixture is supplied to chamber 40 by means vofthe induction tube 56) which is threaded into an aperture in the bottom of depression 33 and extends up into and fills an alined aperture in the bottom of the chamber 40. Tube may be provided withan air-filter 5| at its lowerend but is otherwise unobstructed, or the air-filter may .be omitted and the lower end of tube 50 .connected directly to the 'lower end of the manifold. Within the tube 5|! is a concentric smaller tube 53 providing a space forthe passage-of air between the tubes El] and 53. The upperendof tube I53 is.provided with an .atomizing jet 54 .positioned slightly above the normal float level of the fuel .in the reservoir 30, while the lowerend of the tube 53 is bent and is tightly .fitted intoa suitable aperture in the side wall of the .tube 50, the aperture being positioned well above the-bottom of the reservoir so that fuel may be drawn into the tube -53 to -be atomized through .jet 54 .due both -to the velocity of air passing the jet 54 and-to the slightlyreduced-pressure.inthe chamber 40.

In order to prevent liquid fuel accumulating -in the chambers 4:0 and 4|, 'in .case an excess is atomized and not volatilized, drain holes 56 are :formed in shallow depressions in the bottom walls of the-chambers =40 and 4| so that any such unvolatilized fuel may be returned to the floatchamber 30.

Chamber 4| is provided with a plurality of fuel atomizing tubes '60 each of which may be similar in 'cor1.'=,truction to tube -50, are threaded into similar apertures in the depressions 3-3 and enter the chamber 4| through alined, tightly fitting apertures in the bottom wall 41 of the chamber 4|, the wall 41 forming the separating partition between the chambers "40 and 4! and thezreservoiriit. The upperportionof the chambers 40 and 4| is closed by means of the plate 48 held by screws 49 so that it may be removed for cleaning, inspection, etc.

Rich fuel-air mixture is fed from the premixing chamber 40 to the intake tube I!) for idling of the engine through a relatively small conduit 65 which leads fromthe premixing chamber 40 to the tube In past a needle valve 56 serving to regulate the amount of this rich fuel-air mixture which is fed relative to the air introduced through the tube It). A by-pass conduit 58 is connected with the conduit 65 and also leads to the tube Ill, and is provided with a similar needle valve 69, and a small filter element H3 is interposed between the conduit .68 and the conduit 65. v

Means are provided for variably controlling the communication of one -of the premixin g chambers with the intake tube in accordance with the opening of the throttle l5 so that as the throttle is opened, more of the rich fuelair mixture may be fed from the premixing chamber to the intake tube to maintain a constant fuel-air ratio delivered to the engine. For this purpose, a valve :is provided between the chamber 4| and the tube H) and is adapted to be opened and closed proportionally to the throttle.

As embodied, the butterflyvalve is provided with an upwardly projecting'lug 13 which is connected by link T4 to an eccentric pin 18 'on'plate 19 forming the end of the rotatable inner member 88 of the valve b'etweenthe chamber 4| and the tube '|0. Valve'member 8flis rotatable within the outer member 8| which is threaded into'lan aperture between the chamber and tube, .and the members 8! andare provided withjregistering apertures 82 which are closed by relative rotation of the parts. Innermember 80 is provided with an annular groove 83 into which projects the end of-a screw'85 serving to hold the members against relative axial movement and the link 14 and other parts are so proportioned and positioned that with the butterfly-valve vI'Ei closed, the apertures -82 in the valve are closed,

and the valve is gradually opened proportionally to the openingof the throttle "l5, assuming its fully open position when the throttle I5 is fully open. The valve member 8 is hollow and opens directly into the chamber 4|, 'so that when it is open the maximum amount'o'f rich fuel-air mixture is delivered from the chamber 4| to the tube l0 and the maximum amount of air passes through the tubes 60 to increase the amount of atomized fuel delivered to the premixing chamber 4| for volatilization.

When the throttle I5 is opened quickly, the pressure within the chamber 4| is suddenly reduced and the pressure difference between the chambers '49 and 4| causes valve member .43 to be lifted from the aperture 46 so that an additional amount of rich fuel-air mixture may be delivered to the tube I0 through the valve apertures 82.

"The operation of the described embodiment maybe summarized as follows:

During the idling operation of the engine, air passes throughthe intake tube Ill under considerable suction and is delivered to the engine, This suctionin the tube maylift the valve leaves H very slightly to permit the entry of this air, but the suction is principally communicated through the conduit 55 to cause air to'be drawn through'the tube 5|! pastthe nozzle '54 and due to'the reduced pressure and the induced suction,

fuel is atomized by the jet 54 into the chamber 40, the fuel level always being maintained in the reservoir 30 by fresh fuel delivered through the supply pipe 3!. The atomized fuel is vaporized in the chamber 40, any unvaporized drops collecting on the walls of the chamber and being eventually returned to the reservoir 39 through the aperture 56, and the chamber it is thereby filled with a relatively large volume of air to form the combustible or explosive mixture.

The rich fuel-air mixture from the premixing chamber 49 is fed (for idling) through the conduit 65 to the intake tube and when diluted by the air in the tube forms the homogeneous explosive fuel-air mixture for the engine. Also, some of this mixture is passed through screen 10 to remove all unvaporized fuel and to provide an additional supply of fuel-air mixture to the tube through conduit 68, which is controlled by needle valve 69.

When the engine is operating under load and with the throttle l5 partially or fully open, the fuel-air valve 86, 8| is open to a corresponding degree and rich fuel-air mixture is delivered from the premixing chamber 4! to the intake tube l through the apertures 82, the amount of the fuel-air mixture being properly metered by the degree of opening of the apertures 82. The rich fuel-air mixture in the chamber 4| is replenished by the suction and velocity action of the air drawn thIOLEh the tubes 60 which atomize additional fuel through the jets 54 in these tubes 60 and deliver this atomized fuel to the chamber 4! any unvaporized fuel collecting and draining through the apertures 56 back into the reservoir 39. Thus again substantially saturated fuel-air mixtures is delivered to the tube [0 rather than the customary raw unvaporized spray of fuel.

When the throttle I is opened quickly, as for rapid acceleration in traflic, the pressure in premixing chamber 41 drops rapidly, the pressure in chamber 40 drops only slowly and the resulting difference in pressure causes the valve closure 43 to be opened allowing additional fuel-air mixture to be supplied to the tube H] from both the chambers 40 and ll thereby giving the increased richness which is needed for the heavier load imposed on the engine, and as soon as this pressure difference has been reduced the valve 43 closes so that the further supply of fuel to the engine is at the usual, relatively lean rate.

As will be seen from the foregoing detailed description of the illustrative embodiment of the invention and from the description of its operation, complete volatilization of the fuel supplied to the engine is assured, and because a completely gaseous mixture is being supplied to the manifold and mixture, greater homogeneity of the fuel-air mixture can be obtained and maintained than is possible where the fuel is directly atomized into the intake air. The rate at which fuel is supplied does not depend entirely, nor largely, upon the Venturi action of the various jets at different velocities, but rather the flow of fuel to the engine is primarily controlled by a metering valve which operates on a relatively rich and entirely gaseous fuelair mixture.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom Within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. In a carburetor for internal combustion engines the combination of an air intake passage having an air throttle valve therein, a plurality of premixing chambers connected to the intake passage, a small duct forming the connection from one of said chambers to the intake passage, a variable valve forming the connection from another of said chambers to the intake passage down-stream of the throttle valve, a suction operated valve interconnecting the chambers to connect one to the other when the throttle valve is suddenly opened, means interconnecting the variable valve to the throttle valve to open the variable valve as the throttle valve is opened, a fuel reseroir, air tubes each having an atomizing jet fed by the reservoir for introducing fuel and air into the premixing chambers and means for returning unvolatilized fuel from the premixing chambers to the reser- V011.

2. In a carburetor for internal combustion engines the combination of an air intake passage having an air throttle valve therein, a plurality of premixing chambers connected to the intake passage, a small duct forming the connection from one of said chambers to the intake passage, a variable valve forming the connection from another of said chambers to the intake passage down -stream of the throttle valve, a suction operated valve interconnecting the chambers to connect one to the other when the throttle is suddenly opened, means interconnecting the variable valve to the throttle valve to open the variable valve as the throttle valve is opened, a fuel reservoir, and an atomizing jet fed by the reservoir for introducing fuel and air into the premixing chambers.

3. In a carburetor for internal combustion engines, the combination of an air intake passage having an air throttle valve therein, a plurality of premixing chambers connected to the intake passage, a small duct forming the connection from one of said chambers to the intake passage, a variable valve forming a connection from another of said chambers to the intake passage down-stream of said throttle valve, a suction operated valve interconnecting the chambers, means to open the variable valve as the throttle valve is opened, a fuel reservoir and air tubes each having an atomizing jet fed by the reservoir for introducing fuel and mixing chambers.

4. In a carburetor for internal combustion engines, the combination of an air intake passage having a variable area inlet, an air throttle valve in said intake passage, a plurality of premixing chambers connected to the intake passage, a small idling duct forming the connection from one of said chambers to the intake passage, a variable valve forming a connection from another of said chambers to the intake passage down-stream of said throttle valve, a suction operated valve interconnecting the chambers, means to open the variable valve as the throttle valve is opened, a fuel reservoir, and an atomizing jet fed by the reservoir for introducing fuel and air into the premixing chambers.

RICHARD -W. ENGNATI-I.

air into the pre- 

